Sin, Cos (and Tan) from Triangle in Unit Circle v4

① This GeoGebra example dynamically constructs a right triangle inside the unit circle to visually demonstrate how the sine, cosine, and tangent of an angle α correspond to segment lengths on the axes. ② Core mathematical concepts include trigonometric functions, unit circle definition, right-triangle ratios, and graphing of functions. ③ Construction details: using commands such as Intersect, Circle, Point, Polygon, Angle, Segment, and If, the applet creates the unit circle c, a movable point B, triangle t1, angles α and β, and labeled segments sintick, costick, and tantick for the three functions. A slider or draggable point controls the angle, and a graph of the functions is also plotted. ④ This resource is ideal for high school trigonometry lessons, college precalculus review, and interactive exploration of the geometric meaning of sine, cosine, and tangent in relation to the unit circle.